The new test includes all of the more than 4,800 genes currently known to be linked with rare diseases. Canadian researchers used the test to try to diagnose 20 newborns who had a variety of medical problems. Half of the infants had neurological symptoms, such as seizures. The babies were all being treated in neonatal intensive care units (NICUs).

The gene sequencing panel provided a genetic diagnosis for eight of the infants (40 percent). For two babies, their diagnoses directly affected their medical care, the study authors said.

The findings were published online May 30 in the CMAJ (Canadian Medical Association Journal).

"Next-generation sequencing has the potential to transform the practice of clinical genetics rapidly," Dr. David Dyment, of Children's Hospital of Eastern Ontario, and colleagues wrote.

"In particular, newborns admitted to the NICU with rare and complex diseases may benefit substantially from a timely molecular diagnosis through next-generation sequencing," the study authors added.

Currently, infants with suspected rare genetic diseases typically undergo a large number of tests. It can take a long time, possibly even years, before a diagnosis is made, the researchers said.

"This technique can be performed in a hospital-based laboratory," Dyment stated. "This will allow for diagnoses to be made quickly, providing answers to anxious families and potentially life-saving interventions in some cases."

Dr. Sarah Bowdin, of the clinical and metabolic genetics division at the Hospital for Sick Children in Toronto, wrote in an accompanying commentary: "Enabling the family to understand why their baby is ill can help to assuage the almost universal guilt felt by parents that they did something wrong to cause their baby's illness."

And, Bowdin added, "It can also indicate whether other family members may be at risk of the same disease and provide an accurate recurrence risk for future pregnancies."